Two people are dead and two are in critical condition after a fire in the second-floor apartment of a building on Dovercourt Rd. at Dupont St. early Friday. The Ontario Fire Marshal's Office is investigating.

When Carson T. Foster was awakened by his smoke alarm around 3 a.m. Friday, he at first thought it was malfunctioning.

Only when he smelled smoke and heard people scrambling on the other side of his thin apartment wall did he realize there was a fire next door.

Two people have died after the blaze in a second-floor, four-bedroom apartment at Dovercourt Rd. and Dupont St., while two others remain in critical condition.

Toronto Fire has described the four as “young adults.” One, a man in his 20s, was pronounced dead at the scene, while a woman succumbed to her injuries later in the day. Post-mortems are scheduled for Saturday.

Foster said that when he realized what was happening, he immediately called 911, then rushed to the other side of the building, climbing up the fire escape as the fire raged and windows shattered around him.

“I made it to the opening at the top and yelled inside for people to get out, but I didn’t hear anything, which made me think they were either unconscious or dead,” he said.

Within minutes, Foster heard sirens. “I knew that if I entered,” he said, “I would only be creating another victim.”

Firefighters said there were flames at the rear of the building and poor visibility due to thick, black smoke. The fire was extinguished around 4:45 a.m.

The Toronto Professional Firefighters’ Association said up to 55 firefighters battled the blaze, and reported that there appeared to be no working smoke alarms on the second floor.

One firefighter was also injured, and a cat was found dead.

Ontario Fire Marshal’s Office investigators were trying to determine the cause of the fire, which they believe started in the living room and kitchen area.

Fire Capt. Adrian Ratushniak said damage is estimated at $100,000. He said he believed next of kin of the victims had been notified.

The unit where the fire began is above what appears to be a vacant store. Foster said he did not know or ever even see the four tenants next door, saying people moved in and out of the apartment frequently.

“I was there when (the paramedics) brought them out … It was horrific,” he said. “Like any sort of traumatic event, you wonder if you could have done more.”